Conditional discrimination in mentally retarded adults: the effect of training the component simple discriminations.
Teach both sample and comparison together with blocked-trial fading—splitting them fails.
01Research in Context
What this study did
Two adults with intellectual disability could not do arbitrary matching-to-sample. The team first tried teaching the parts separately: sample-only and comparison-only trials. That failed. They then combined both parts in blocked-trial fading. Only this package produced accurate matching.
What they found
Component training alone was not enough. Learners needed the full conditional task from the start, with trials grouped by stimulus set and prompts slowly removed. Once this happened, both adults hit high accuracy.
How this fits with other research
Tenneij et al. (2009) extends the finding. They also worked with adults with ID and cut errors in half by showing comparisons five seconds before the sample. The 1989 study showed you must keep both parts together; the 2009 tweak shows timing also matters.
LeFrancois et al. (1993) extends further. After matching picture to word, the same adults spelled new words without direct teaching. The 1989 paper got matching; the 1993 paper shows matching can bloom into spelling and equivalence classes.
Ayres‐Pereira et al. (2025) supersedes the method. They formed equivalence classes in every adult by placing highly similar stimuli side-by-side. The 1989 blocked-trial fading worked, but simultaneous comparison presentation is now the stronger choice.
Why it matters
If your client with ID keeps failing matching-to-sample, do not break the task into separate pieces. Run the full conditional task from day one. Use blocked-trial fading or, better, show all comparisons at once. Once matching is solid, add spelling or reading goals; equivalence may emerge without extra teaching.
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02At a glance
03Original abstract
Two subjects with retardation who exhibited generalized identity matching, but who had extensive histories of failure to acquire arbitrary matching, were exposed to a series of conditions designed to train separately the components of a two-choice conditional discrimination. First, the successive discrimination between the sample stimuli was established by programming a different schedule of reinforcement in the presence of each sample stimulus. Schedule performance was acquired and maintained by both subjects, but neither acquired arbitrary matching. To train the simultaneous discrimination between the comparison stimuli, 1 subject was then exposed to a series of simple discrimination reversals and subsequently failed to acquire arbitrary matching. Both subjects acquired arbitrary matching under a procedure that maintained both the sample and the comparison discrimination by first presenting entire sessions composed of one sample-comparison relation and then gradually reducing the number of consecutive trials with the same sample until sample presentation was randomized (schedule performance was maintained). Removal of the schedule requirement had no effect on arbitrary matching accuracy. Both subjects subsequently demonstrated control by relations symmetric to the trained relations.
Journal of the experimental analysis of behavior, 1989 · doi:10.1901/jeab.1989.52-1